With the recent increase in the number of people enjoying baseball, a so-called screen baseball system has emerged, which overcomes the limitations of playing baseball in a large baseball stadium and allows people to enjoy playing a virtual baseball game even in a small indoor space while experiencing virtual reality.
Typically, a screen baseball system is installed in an indoor space and has a batting area with a space of a predetermined size in which a user can bat and a screen capable of displaying a virtual baseball stadium. When a pitching machine installed behind the screen pitches a ball toward the batting area, a user who is ready to hit the ball in the batting area hits the ball pitched by the pitching machine. At this time, a sensing device senses the motion of the pitched ball and the motion of the ball hit by the user. Subsequently, based on the result of sensing, whether the pitched ball is a strike or a ball is determined, and an image simulating the trajectory of the hit ball is realized on the screen.
In the screen baseball system, a hole is formed in the screen on which a baseball simulation image is projected, and the pitching machine installed behind the screen pitches a ball toward the batting area through the hole formed in the screen.
Examples of such a screen baseball system using a pitching machine are disclosed in a considerably large number of related art documents, such as Korean Patent Application No. 10-2013-0013688, Korean Patent Application No. 10-2014-0058124, Korean Patent Application No. 10-2010-0079368, Korean Patent Application No. P1990-7002659, Japanese Patent Application Publication No. H09-276467, and Korean Patent Application No. P1994-0023057.
In most conventional screen baseball systems, including the above-described related art documents, a hole having sufficient size to allow a baseball to pass therethrough is formed in the screen, and the pitching machine installed behind the screen pitches a ball toward the batting area through the hole formed in the screen. As a result, when an image is projected on the screen, the image is not displayed on the hole, through which the baseball passes, but rather, the pitching machine is exposed through the hole. Consequently, the user's immersion in the image projected on the screen is greatly deteriorated, and the user's interest in the screen baseball game is greatly reduced.
Technology capable of controlling the hole in the screen so as to be open and closed such that the hole in the screen is open only when the pitching machine pitches a ball and such that the hole in the screen is closed when the pitching machine pitches no ball, whereby the image projected on the screen is completely visible rather than being partially omitted in order to prevent deterioration of user's immersion in screen baseball games through the image projected on the screen, has been filed in the name of the present applicant and has been accorded Korean Patent Application No. 10-2015-0181552.
The related art documents, including Korean Patent Application No. 10-2013-0013688, disclose technology in which, in order to realize various release points based on a pitching operation of a virtual pitcher on the image projected on the screen, a plurality of pitching holes, through which balls are pitched for the respective release points, is formed in the screen and in which, when a ball is to be pitched through a certain release point, the pitching machine installed behind the screen is moved upwards, downwards, leftwards, and rightwards such that the ball is pitched through a pitching hole corresponding to the certain release point.
In general, however, the pitching machine has quite large volume and weight. For this reason, an additional high-power driving device is required in order to move the pitching machine upwards, downwards, leftwards, and rightwards. In addition, it is very difficult to control the pitching machine so as to be accurately positioned behind the respective pitching holes in the screen. Above all, since a plurality of holes is formed in the screen, the entire image projected on the screen is not visible, user's immersion in the image is greatly deteriorated, and user's interest in screen baseball games is seriously reduced.
Also, even in the case in which the construction of opening and closing the hole in the screen disclosed in Korean Patent Application No. 10-2015-0181552, filed in the name of the present applicant, is applied to a plurality of holes in the screen, a plurality of additional driving motors must be provided, whereby the screen baseball system is complicated, cost is greatly increased, and the possibility of malfunction or breakdown of the screen baseball system is greatly increased. Above all, in the case in which a plurality of opening and closing structures is provided, the aesthetic appearance of the screen baseball system that is visible to users is greatly spoiled.